Unless otherwise indicated herein, the materials described in this section are not prior art to the claims and are not admitted to be prior art by inclusion in this section.
Cellular wireless networks typically include a number of base stations that radiate to define wireless coverage areas, such as cells and/or cell sectors, in which user equipment devices (UEs) such as cell phones, “smart” phones, tablet computers, tracking devices, embedded wireless modules, and other wirelessly equipped communication devices, can operate. Each base station forms part of a Radio Access Network (RAN) that is coupled by a “backhaul” to a “core” network, which in turn provides connectivity with one or more transport networks, such as the public switched telephone network (PSTN) for voice communications and/or the Internet for voice and/or data communications, as well as data services, for instance.
In general, a wireless network operates in accordance with a particular air interface protocol or radio access technology, with communications from the base stations to UEs defining a downlink or forward link and communications from the UEs to the base stations defining an uplink or reverse link. Examples of existing air interface protocols include, without limitation, Orthogonal Frequency Division Multiple Access (OFDMA (e.g., Long Term Evolution (LTE) or Wireless Interoperability for Microwave Access (WiMAX)), Code Division Multiple Access (CDMA) (e.g., 1×RTT and 1×EV-DO), and Global System for Mobile Communications (GSM), Universal Mobile Telecommunications Service (UMTS) among others. Each protocol defines its own procedures for registration of UEs, initiation of communications, allocation of bandwidth for UE communications, handoff/handover between coverage areas, and functions related to air interface communication.
When a UE enters into a cell or sector (or more generally, coverage area) of a base station, the UE may attach, register, or otherwise associate with the base station, and the base station may then serve the UE on one or more carriers. The base station may then be referred to as the UE's “serving” base station. In practice, the process of serving the UE may involve the serving base station allocating use of particular air interface resources, such as traffic channels or portions thereof, to carry data communications to and from the UE, and managing transmission on those resources, such as controlling what modulation scheme is used for the transmissions.
With this arrangement, a UE within the coverage area of the wireless network may engage in air interface communication with a base station. This arrangement enables UEs to communicate via the base station with various remote network entities or with other UEs served by the base station or by one or more other base stations.
A cellular wireless network is typically operated by a service provider that offers network access and service to users or subscribers. In order to ensure that only authorized UEs may gain access to a service provider's network and its services, various types of security techniques may be implemented. These may include a mutual authentication in which the network authenticates the UE and the UE authenticates the network. The network will also typically need to know “secret information” of a user or subscriber in order to be able to offer services.
A service provider may employ a centralized “Home Subscriber Server” (“HSS”) in its core network for provisioning subscribers and their UEs, as well as maintaining a database of subscribers and their provisioned services. When a subscriber accesses the wireless network via the subscriber's UE, the HSS provides authentication “vectors” to a “Mobility Management Entity” (“MME”), which are used to authenticate the UE with the network, and to authenticate the network with the UE. The centralized HSS stores information regarding the subscriber's profile and one or more service attributes.
Cellular wireless networks are also used for public safety networks, either as standalone networks or overlaid on existing networks of service providers. A public safety network will typically have its own HSS for its personnel and their associated UEs, yet must also be able to operate under circumstances in which a RAN or part of a RAN loses connectivity with the core network (e.g., in the event of a natural disaster). In order to establish and/or maintain at least some level of operability when RAN-core connectivity is interrupted, public safety networks employ a form of portable network customarily referred to as a “deployable.” Each deployable integrates the functionality of a RAN and many aspects of the core network, including a local HSS that duplicates the centralized HSS, in a standalone unit. When deployed in a geographic region where RAN-core connectivity has been lost, a deployable makes it possible for emergency personnel to authenticate their UEs with the cellular wireless network of the deployable (and vice versa), and thereby be afforded wireless communications within an area served by the deployable.